U0121 = Data bus, anti-lock brake system (ABS) control module - no communication
The DTC will set if a valid CAN ID was not received in the from the ABS module
or The ECM/PCM doesn't receive a Bus Message from the Anti-lock Brake Module.
U0415 = Invalid data received - anti-lock brake system (ABS) control module
U0415-Implausible data received from ABS
When the TCM detects an incorrect CAN ID from the ABS control module.
U0402 = Invalid data received - transmission control module (TCM)
An error message has been received over the bus from the Transmission Control Module (TCM).
U0402–IMPLAUSIBLE DATA RECEIVED FROM TCM (FDCM)
The Final Drive Control Module is receiving implausible data for gear or PRNDL position from the TCM
What happened right before you got the codes? Battery go dead? Jump start?
Any recent Mods or changes you made?
Most of the above could be due to a chafed, loose, or burnt wire. If they are intermittent.
If they are continuous, then most likely your ABS module or PCM is shot, or there are other modules which are not correctly programmed. (VIN Missing/Mismatch, TIPM, battery or ignition related)
Make sure you have + and - to the ABS module.
Check fuses J6 and J7 are good and are seated correctly.
Black 47 way connector on the left inboard of the TIPM.
Check the following Pins.
Pin 1 (TN/RD wire) B+, Pin 13 (BK) -,
Pin 25 (DG/RD wire) B+, Pin 38 (BK wire) -.
Other then that you are looking at a dealer visit...
Thank you i will go down that list tomorrow
First time it happened i only had the code u0121 when i was driving and then nothing for a long time maybe a few months. Then the second time
i got the u0121 on a morning going to start the car. 3rd the same but today the 4th time it came up with all 3 while i was driving but also lost the speedo as well after say 10 meters the speedo came back and only the abs and engine light were on the dash. after clearing codes each time nothing shows up.
Other stuff that maybe related
.Radio randomly resets time after a few days
.Last week the power seats forward would not work until i pressed the memory button (This also caused the radio to reset) and after worked fine. I keep testing the seat and it works perfect only that one time it did not work and reset the radio.
.Cleaned battery terminals again
.New ground to body nearest the abs module straight to battery
.Removed fuze box and checked all connections/ cleaned with contact cleaner